1. Field of the Invention
This invention relates to computer systems, and particularly to computer systems having one or more fans located within an enclosure for providing forced air cooling of components located within the enclosure.
2. Description of the Related Art
A typical computer system includes multiple electronic components, including a central processing unit or "processor", positioned within an enclosure. During operation, such electronic components dissipate electrical power (i.e., transform electrical energy into heat energy). At the same time, several key operating parameters of semiconductor electronic devices typically vary with temperature, and reliable device operation within specifications occurs only within a defined operating temperature range. For example, specified performance of a processor is typically achieved only when the temperature of the processor is maintained below a specified maximum operating temperature. Operation of the processor at a temperature above the maximum operating temperature may result in irreversible damage to the processor. In addition, it has been established that the reliabilities of semiconductor electronic devices decrease with increasing operating temperature.
The heat energy produced by electronic components during operation must thus be removed to a surrounding ambient at a rate which ensures operational and reliability requirements are met. As component speeds and capabilities increase, so does the amount of electrical power dissipated by the components during operation. Cooling mechanisms employed by computer systems must thus transfer more heat energy from the computer system enclosure to the surrounding ambient.
Today, a typical computer system includes at least two fans located within the enclosure. A first fan is typically located within a power supply unit which supplies electrical power to other system components. The first fan exhausts air within the enclosure through an opening in a rear panel of the enclosure. The resulting vacuum created within the enclosure causes ambient air surrounding the enclosure to be drawn into the enclosure through various openings in the enclosure. The air entering the enclosure flows over the components within the enclosure, absorbing heat energy from the components before being expelled through the rear panel by the fan. A second fan is attached to a heat sink mounted to the processor. The second fan circulates air through the heat sink, and is dedicated to cooling the processor.
Fans are rotating electromechanical devices which produce acoustic noise and fail relatively often (i.e., have relatively short lives). When a fan fails, the components which rely on cooling air provided by the fan can, and often do, fail as well. It would thus be desirable to have a computer system which provides adequate component cooling with a minimum number of fans.